Devices can use a single-wire bus for bidirectional communications. A host device can be connected with a slave device via a single-wire bus. Both the host device and the slave device can be connected to ground to complete the circuit. In some instances, a slave device is implemented as an integrated circuit that is packaged in a housing that contains three or more pins: one for the single-wire bus, one for an input voltage, and one for ground. In some instances, a slave device is implemented as an integrated circuit that is packaged in a housing that contains two pins: one for the single-wire bus and one for ground. The slave device can be powered parasitically from the single-wire bus. A single-wire bus can interconnect two or more devices.